Worksheet: Converting Concentrations to pH and pOH

In this worksheet, we will practice converting between hydronium and hydroxide ion concentrations in water and the corresponding values of pH and pOH.

Q1:

At 25C, the hydronium ion concentration of vinegar is approximately 4.0×10 M. To 1 decimal place, what is the corresponding value of the pOH?

Q2:

To 1 decimal place, what is the pH of a 0.0125 M solution of potassium hydroxide, KOH?

Q3:

What is the pOH of a 0.0125 M solution of potassium hydroxide, KOH?

  • A12.1
  • B4.01
  • C1.90
  • D0.0125
  • E9.99

Q4:

To 1 decimal place, what is the pH of 0.21 MNaOH at 25C? Assume that NaOH ionizes completely.

Q5:

To 2 decimal places, what is the pH of 0.000071 MBa(OH)2 at 25C? Assume that Ba(OH)2 ionizes completely.

Q6:

To 2 decimal places, what is the pOH of 0.21 MNaOH at 25C? Assume that NaOH ionizes completely.

Q7:

To 2 decimal places, what is the pOH of 2.5 MKOH at 25C? Assume that KOH ionizes completely.

Q8:

To 1 decimal place, what is the pH of 2.5 MKOH at 25C? Assume that KOH ionizes completely.

Q9:

To 2 decimal places, what is the pOH of 0.000071 MBa(OH)2 at 25C? Assume that Ba(OH)2 ionizes completely.

Q10:

Calculate to 3 significant figures the hydroxide concentration of a solution with a pH of 6.52 at 25C. The self-ionization constant of water, 𝐾w, is 1.00×10 at this temperature.

  • A 6 . 7 9 × 1 0 M
  • B 3 . 3 1 × 1 0 M
  • C 8 . 9 5 × 1 0 M
  • D 5 . 0 6 × 1 0 M
  • E 3 . 0 1 × 1 0 M

Q11:

Coffee has a pH of about 5.1. Calculate to 2 significant figures the hydroxide ion concentration of coffee at 25C.

  • A 1 . 2 × 1 0 M
  • B 1 . 3 × 1 0 M
  • C 6 . 3 × 1 0 M
  • D 1 . 6 × 1 0 M
  • E 7 . 9 × 1 0 M

Q12:

To 2 decimal places, what is the pH of 0.0143 MNaOH at 25C? Assume that NaOH ionizes completely.

Q13:

To 1 decimal place, what is the pOH of 3.0 MHNO3 at 25C? Assume that HNO3 ionizes completely.

Q14:

To 2 decimal places, what is the pOH of 0.0143 MNaOH at 25C? Assume that NaOH ionizes completely.

Q15:

To 1 decimal place, what is the pOH of 0.0031 MCa(OH)2 at 25C? Assume that Ca(OH)2 ionizes completely.

Q16:

To 1 decimal place, what is the pH of 0.0031 MCa(OH)2 at 25C? Assume that Ca(OH)2 ionizes completely.

Q17:

The pOH of a solution of a base is 4.17, at 25C. What is the H+ concentration?

  • A 4 . 6 6 × 1 0 M
  • B 2 . 2 7 × 1 0 M
  • C 1 . 4 8 × 1 0 M
  • D 6 . 7 6 × 1 0 M

Q18:

To 1 decimal place, what is the pOH of a 0.000259 M aqueous HClO4 solution at 25C? Assume that HClO4 is completely ionized.

Q19:

To 1 decimal place, what is the pOH of 0.200 MHCl at 25C? Assume that HCl ionizes completely.

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